PSR-4 相关示例

以下是 PSR-4 规范的相关示例代码：

闭包的实现示例

  1. <?php
  2. /**
  3.  * 一个具体项目的实例
  4.  * 
  5.  * 当使用 SPL 注册此自动加载器后，执行以下语句将从 
  6.  * /path/to/project/src/Baz/Qux.php 载入 \Foo\Bar\Baz\Qux 类：
  7.  * 
  8.  *      new \Foo\Bar\Baz\Qux;
  9.  *      
  10.  * @param string $class 完整的类名
  11.  * @return void
  12.  */
  13. spl_autoload_register(function ($class) {
  15.     // 具体项目命名空间前缀
  16.     $prefix = 'Foo\\Bar\\';
  18.     // 命名空间前缀的基目录
  19.     $base_dir = __DIR__ . '/src/';
  21.     // 判断类名是否具有本命名空间前缀
  22.     $len = strlen($prefix);
  23.     if (strncmp($prefix, $class, $len) !== 0) {
  24.         // 不含本命名空间前缀，退出本自动载入器
  25.         return;
  26.     }
  28.     // 截取相应类名
  29.     $relative_class = substr($class, $len);
  31.     // 将命名空间前缀替作为文件基目录，然后
  32.     // 将类名中的命名空间分隔符替换成文件分隔符,
  33.     // 最后添加 .php 后缀
  34.     $file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';
  36.     // 如果以上文件存在，则将其载入
  37.     if (file_exists($file)) {
  38.         require $file;
  39.     }
  40. });

类的实现示例

下面是一个可处理多命名空间的类实例

  1. <?php
  2. namespace Example;
  4. /**
  5.  * An example of a general-purpose implementation that includes the optional
  6.  * functionality of allowing multiple base directories for a single namespace
  7.  * prefix.
  8.  * 
  9.  * Given a foo-bar package of classes in the file system at the following
  10.  * paths ...
  11.  * 
  12.  *     /path/to/packages/foo-bar/
  13.  *         src/
  14.  *             Baz.php             # Foo\Bar\Baz
  15.  *             Qux/
  16.  *                 Quux.php        # Foo\Bar\Qux\Quux
  17.  *         tests/
  18.  *             BazTest.php         # Foo\Bar\BazTest
  19.  *             Qux/
  20.  *                 QuuxTest.php    # Foo\Bar\Qux\QuuxTest
  21.  * 
  22.  * ... add the path to the class files for the \Foo\Bar\ namespace prefix
  23.  * as follows:
  24.  * 
  25.  *      <?php
  26.  *      // instantiate the loader
  27.  *      $loader = new \Example\Psr4AutoloaderClass;
  28.  *      
  29.  *      // register the autoloader
  30.  *      $loader->register();
  31.  *      
  32.  *      // register the base directories for the namespace prefix
  33.  *      $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/src');
  34.  *      $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/tests');
  35.  * 
  36.  * The following line would cause the autoloader to attempt to load the
  37.  * \Foo\Bar\Qux\Quux class from /path/to/packages/foo-bar/src/Qux/Quux.php:
  38.  * 
  39.  *      <?php
  40.  *      new \Foo\Bar\Qux\Quux;
  41.  * 
  42.  * 以下代码将由 /path/to/packages/foo-bar/tests/Qux/QuuxTest.php 
  43.  * 载入 \Foo\Bar\Qux\QuuxTest 类
  44.  * 
  45.  *      <?php
  46.  *      new \Foo\Bar\Qux\QuuxTest;
  47.  */
  48. class Psr4AutoloaderClass
  49. {
  50.     /**
  51.      * An associative array where the key is a namespace prefix and the value
  52.      * is an array of base directories for classes in that namespace.
  53.      *
  54.      * @var array
  55.      */
  56.     protected $prefixes = array();
  58.     /**
  59.      * 在 SPL 自动加载器栈中注册加载器
  60.      * 
  61.      * @return void
  62.      */
  63.     public function register()
  64.     {
  65.         spl_autoload_register(array($this, 'loadClass'));
  66.     }
  68.     /**
  69.      * 添加命名空间前缀与文件基目录对
  70.      *
  71.      * @param string $prefix 命名空间前缀
  72.      * @param string $base_dir 命名空间中类文件的基目录
  73.      * @param bool $prepend 为 True 时，将基目录插到最前，这将让其作为第一个被搜索到，否则插到将最后。
  74.      * @return void
  75.      */
  76.     public function addNamespace($prefix, $base_dir, $prepend = false)
  77.     {
  78.         // 规范化命名空间前缀
  79.         $prefix = trim($prefix, '\\') . '\\';
  81.         // 规范化文件基目录
  82.         $base_dir = rtrim($base_dir, '/') . DIRECTORY_SEPARATOR;
  83.         $base_dir = rtrim($base_dir, DIRECTORY_SEPARATOR) . '/';
  85.         // 初始化命名空间前缀数组
  86.         if (isset($this->prefixes[$prefix]) === false) {
  87.             $this->prefixes[$prefix] = array();
  88.         }
  90.         // 将命名空间前缀与文件基目录对插入保存数组
  91.         if ($prepend) {
  92.             array_unshift($this->prefixes[$prefix], $base_dir);
  93.         } else {
  94.             array_push($this->prefixes[$prefix], $base_dir);
  95.         }
  96.     }
  98.     /**
  99.      * 由类名载入相应类文件
  100.      *
  101.      * @param string $class 完整的类名
  102.      * @return mixed 成功载入则返回载入的文件名，否则返回布尔 false
  103.      */
  104.     public function loadClass($class)
  105.     {
  106.         // 当前命名空间前缀
  107.         $prefix = $class;
  109.         // work backwards through the namespace names of the fully-qualified
  110.         // class name to find a mapped file name
  111.         while (false !== $pos = strrpos($prefix, '\\')) {
  113.             // retain the trailing namespace separator in the prefix
  114.             $prefix = substr($class, 0, $pos + 1);
  116.             // the rest is the relative class name
  117.             $relative_class = substr($class, $pos + 1);
  119.             // try to load a mapped file for the prefix and relative class
  120.             $mapped_file = $this->loadMappedFile($prefix, $relative_class);
  121.             if ($mapped_file) {
  122.                 return $mapped_file;
  123.             }
  125.             // remove the trailing namespace separator for the next iteration
  126.             // of strrpos()
  127.             $prefix = rtrim($prefix, '\\');   
  128.         }
  130.         // 找不到相应文件
  131.         return false;
  132.     }
  134.     /**
  135.      * Load the mapped file for a namespace prefix and relative class.
  136.      * 
  137.      * @param string $prefix The namespace prefix.
  138.      * @param string $relative_class The relative class name.
  139.      * @return mixed Boolean false if no mapped file can be loaded, or the
  140.      * name of the mapped file that was loaded.
  141.      */
  142.     protected function loadMappedFile($prefix, $relative_class)
  143.     {
  144.         // are there any base directories for this namespace prefix?
  145.         if (isset($this->prefixes[$prefix]) === false) {
  146.             return false;
  147.         }
  149.         // look through base directories for this namespace prefix
  150.         foreach ($this->prefixes[$prefix] as $base_dir) {
  152.             // replace the namespace prefix with the base directory,
  153.             // replace namespace separators with directory separators
  154.             // in the relative class name, append with .php
  155.             $file = $base_dir
  156.                   . str_replace('\\', DIRECTORY_SEPARATOR, $relative_class)
  157.                   . '.php';
  158.             $file = $base_dir
  159.                   . str_replace('\\', '/', $relative_class)
  160.                   . '.php';
  162.             // 当文件存在时，在入之
  163.             if ($this->requireFile($file)) {
  164.                 // 完成载入
  165.                 return $file;
  166.             }
  167.         }
  169.         // 找不到相应文件
  170.         return false;
  171.     }
  173.     /**
  174.      * 当文件存在，则从文件系统载入之
  175.      * 
  176.      * @param string $file 需要载入的文件
  177.      * @return bool 当文件存在则为 True，否则为 false
  178.      */
  179.     protected function requireFile($file)
  180.     {
  181.         if (file_exists($file)) {
  182.             require $file;
  183.             return true;
  184.         }
  185.         return false;
  186.     }
  187. }

单元测试

以下是上面代码单元测试的一种实现：

```php
<?php
namespace Example\Tests;

class MockPsr4AutoloaderClass extends Psr4AutoloaderClass
{
protected $files = array();

  1. public function setFiles(array $files)
  2. {
  3.     $this->files = $files;
  4. }
  6. protected function requireFile($file)
  7. {
  8.     return in_array($file, $this->files);
  9. }

}

class Psr4AutoloaderClassTest extends \PHPUnit_Framework_TestCase
{
protected $loader;

  1. protected function setUp()
  2. {
  3.     $this->loader = new MockPsr4AutoloaderClass;
  5.     $this->loader->setFiles(array(
  6.         '/vendor/foo.bar/src/ClassName.php',
  7.         '/vendor/foo.bar/src/DoomClassName.php',
  8.         '/vendor/foo.bar/tests/ClassNameTest.php',
  9.         '/vendor/foo.bardoom/src/ClassName.php',
  10.         '/vendor/foo.bar.baz.dib/src/ClassName.php',
  11.         '/vendor/foo.bar.baz.dib.zim.gir/src/ClassName.php',
  12.     ));
  14.     $this->loader->addNamespace(
  15.         'Foo\Bar',
  16.         '/vendor/foo.bar/src'
  17.     );
  19.     $this->loader->addNamespace(
  20.         'Foo\Bar',
  21.         '/vendor/foo.bar/tests'
  22.     );
  24.     $this->loader->addNamespace(
  25.         'Foo\BarDoom',
  26.         '/vendor/foo.bardoom/src'
  27.     );
  29.     $this->loader->addNamespace(
  30.         'Foo\Bar\Baz\Dib',
  31.         '/vendor/foo.bar.baz.dib/src'
  32.     );
  34.     $this->loader->addNamespace(
  35.         'Foo\Bar\Baz\Dib\Zim\Gir',
  36.         '/vendor/foo.bar.baz.dib.zim.gir/src'
  37.     );
  38. }
  40. public function testExistingFile()
  41. {
  42.     $actual = $this->loader->loadClass('Foo\Bar\ClassName');
  43.     $expect = '/vendor/foo.bar/src/ClassName.php';
  44.     $this->assertSame($expect, $actual);
  46.     $actual = $this->loader->loadClass('Foo\Bar\ClassNameTest');
  47.     $expect = '/vendor/foo.bar/tests/ClassNameTest.php';
  48.     $this->assertSame($expect, $actual);
  49. }
  51. public function testMissingFile()
  52. {
  53.     $actual = $this->loader->loadClass('No_Vendor\No_Package\NoClass');
  54.     $this->assertFalse($actual);
  55. }
  57. public function testDeepFile()
  58. {
  59.     $actual = $this->loader->loadClass('Foo\Bar\Baz\Dib\Zim\Gir\ClassName');
  60.     $expect = '/vendor/foo.bar.baz.dib.zim.gir/src/ClassName.php';
  61.     $this->assertSame($expect, $actual);
  62. }
  64. public function testConfusion()
  65. {
  66.     $actual = $this->loader->loadClass('Foo\Bar\DoomClassName');
  67.     $expect = '/vendor/foo.bar/src/DoomClassName.php';
  68.     $this->assertSame($expect, $actual);
  70.     $actual = $this->loader->loadClass('Foo\BarDoom\ClassName');
  71.     $expect = '/vendor/foo.bardoom/src/ClassName.php';
  72.     $this->assertSame($expect, $actual);
  73. }

}